Compressor unloading apparatus



p 4, 1956 A. B. NEWTON 2,761,616

COMPRESSOR UNLOADING APPARATUS Filed April 19, 1955 2 Sheets-Sheet 1 ATTORNE Sept. 4, 1956 A. B. NEWTON COMPRESSOR UNLOADING APPARATUS 2 Sheets-Sheet 2 Filed April 19, 1955 ATTORNEY United States Patent 2,761,616 COMPRESSOR UNL'OADING APPARATUS Alwin B. Newton, Wichita, Kans., assignor to The Coleman Company, Inc., Wichita, Kans., a corporation of Kansas 9 Application April 19, 1955, Serial No. 502,417

11 Claims. (Cl. 230-31) This invention relates to a compressor unloading apparatus, and more particularly, to a fluid pressure operated piston and valve arrangement for controlling the flow of fluid into a compressor chamber.

One of the main objects of this invention is to provide an apparatus which delays the loading of a compressor until after the compressor motor has started. Another object is to provide a valve which is operated by fluid pressure and which moves to closed position for loading the compressor only after the compressor motor has operated a predetermined length of time, or after a predetermined condition is satisfied. A further object is to provide a valve for a compressor which has a primary and secondary flow passage therethrough, the primary passage allowing fluid to flow toward and from the compressor chamber, and the secondary passage permitting the flow of fluid only in a single direction toward the compressor chamber, and means for closing the primary passage after the compressor motor has started to operate. A still further object is to provide aconeshape valve cage biased to open position and movable under the influence of oil pressure to closed position for loading the compressor. Additional objects and 'ad-, vantages will appear as the specification proceeds.

Embodiments of the invention are illustrated in the accompanying drawings, in which:

The compressor comprises a casing 1 which has a top portion divided by a wall 2 into a pair of compression chambers 3 and 4. While only a pair of chambers are shown in Figs. 1 and 3, it is apparent that a greater or smaller number may be provided, depending upon the particular use for which the compressor is to be adapted. The lower portion of the casing carries crank shaft 5 which has eccentric portions 6 and 7 and which may be rotated by any suitable means, as for instance, by an internal combustion engine. Cylinder yokes 9 and 10 are slidably attached to the eccentric portions of the crank shaft 5 in the customary manner, as illustrated in Fig. 1. Yokes 9 and 10 have bearings securing them to pistons 12 and 13 which are slidably mounted within chambers 3 and 4 respectively.

A continuous chain 11 extends about one end of the shaft 5 and is preferably connected to a gear-type pump 14 at the lower portion of casing 1. Since the pump structure is well known in the art, it is believed that a detailed description herein is unnecessary. Pump 14 is immersed in a pool of oil or other liquid 15 at the bot tom of casing 1, and drives the oil into passage 16 upon the rotation of crank shaft 5.

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compression chambers 3 and 4. Since both the valve units 17 and 18, as shown in Fig. 1, are identical in structure and operation, only one of these units will be described in detail. Valve unit 17 comprises a generally tubular valve casing 19 having an opening 20 in its side wall and another opening 21 in one end to provide a flow passage therethrough leading into compression chamher 4. For purposes of clarity, this passage will be referred to as the primary flow passage.

Extending inwardly from the inner surface of casing 19 and substantially midway between opening 20 and the open lower end of the valve casing is a ledge or stop 22 which reduces the inner diameter of the lower portion of the casing and which provides an annular valve seat on its top surface. An annular lip 23 extends inwardly about opening 21 at the lowermost portion of the primary flow passage through casing 19.

'Within the primary passage is a movable valve cage 24 having the general configuration of a hollow cone having a tubular portion 25 extending downwardly from its base. The tubular portion of the cage has an outer diameter less than the diameter of the cones base, so that at the juncture of the tubular portion and the base of the conical portion there is an outwardly projecting peripheral ridge 26 which comprises an annular valve portion adapted for abutting or seating against the annular ledge or stop 22 of the valve casing and for closing the primary flow passage.

As illustrated in Figure 1, the tubular and conical portions of the cage are in communication with each other. Moreover, the wall of the cone is provided with a plurality of openings 27 and the free end 28 of the tubular portion is open to provide a secondary flow passage through the valve cage which also communicates with the compression chamber 4.

The outer diameter of the tubular portion 25 of the valve cage is less than the inner diameter of the lower portion of the casing below ledge 22, so' that when the valve cage is unseated the primary flow passage is open and in communication with compression chamber 4. When the valve cage is seated against ledge 22, however,

. only the secondary flow passage through the valvecage units 17 and 18 through which fluid must pass to enter for reciprocal movement between the movable valve seat 29 and the annular lip 23 of the casing 19. As is best seen in Fig. 2, this disc-shaped valve member is provided with serrated edges sothat when the valve seats against the valve seat 29 of the movable cage, the secondary flow passage through the cage is sealed, but when the discshaped member rests against annular lip 23, the flow passages may communicate with the compression chamber about the serrated edges of member 30. Moreover, when the valve cage is unseated from ledge 22, fluid may pass in either direction around the outside of the valve cage and about the serrated edges of the disc-shaped valve member whether that member is or is not in seated position against cage 24.

The top portion of easing 1 also encloses an exhaust chamber 31, shown in Figs. 1 and 3 as a chamber adjacent to and interposed between the valve units 17 and 18. The gases or fluids compressed in the compression chambers 3 and 4 may pass into the exhaust chamber through pops 33 and 34 respectively, and leave the exhaust chamber through opening 35 in the casing wall.

Valve seats are provided around ports 33 and 34, and valve members 36 and 37 are movably mounted within the exhaust chamber for movement to unseated positions 3 when the respective pistons move upwardly during the compression strokes and for movement to seated or closed position when the pistons move downwardly during the intake strokes. Therefore, fluid which has once entered the exhaust chamber cannot re-enter the compression chambers.

The valve members 36 and 37 are maintained in operating position by lateral extensions 38 and 39 at the uppermost portion of wall 2. Each lateral extension is equipped with a plurality of downwardly extending peripheral fingers, such as the fingers 40, 41 shown in Fig. l, which retain the valve members for operation while at the same time allow fluid to flow into the exhaust chamber between the downwardly extending fingers. It may also be desirable to bias the valve members 36, 37 to closed or seated positions by spring means, such as helical springs 42, 43.

The valve cages, such as valve cage 24, are riveted or fastened by any other suitable means to movable cupshaped pistons 44, 45 which slide within piston chambers 46, 47 within the upper tubular portions of valve casings 19, 18. Each of the chamber are sealed by covers 48, 49 which are apertured so that the chambers communicate with passages 50 and 51 respectively. Each valve cage and piston unit may be biased upwardly to open or unseated position by spring means, such as springs 57, 58 disposed between the cup-shaped pistons and the annular ledges provided by the valve casings.

A valve 52 is interposed between passages 50, 51 and 16 to control the flow of a pressure fluid, such as oil, to chambers 46, 47. Valve 52 is of customary construction and is adapted to shut off the flow of oil to either chamber 46 or chamber 47, or both, depending upon the manual or automatic setting of valve stem 53. Bleed lines 54 and 55 extend from passages 50 and 51 respectively, and carry oil from chambers 46 and 47 into passage 56 and back to the lower portion of easing 1 when passages 50 and 51 are closed. The bleed lines which connect with passages 50 and 51 are small in diameter and, therefore, have a high resistance to the flow of oil. Thus, oil flowing through the open valve 52 increases the pressure in lines 50 and 51 and in chambers 46 and 47.

While I have shown valve 52 adapted to interrupt the flow of fluid to chambers 46 and 47, it is apparent that the same result might be obtained if the valve operated to close the bleed lines 54, 55 instead of opening the oil lines. Moreover, other suitable hydraulic systems for controlling the pressures in chambers 46 and 47 might be used, such as a controller responsive to suction pressure changes, as is well known in the art.

The operation of my invention is as follows: When the compressor is idle, no pressure fluid is supplied by pump 14 to chamber 46 and valve cage 24 is maintained in unseated position by spring 57, thereby leaving the primary flow passage open. As the crank shaft starts to rotate and piston 13 moves downwardly, vaporized refrigerant or other gaseous fluid flows through opening 25), through the primary flow passage of valve casing 19, around the serrated edges of disc-shaped valve member 30, and into the compression chamber 4. .As the piston 13 moves upwardly, the gas is directed back through the open primary passage and out opening 20. Therefore, during the initial revolutions of crank shaft 5, there is no load upon the compressor and there is substantially no work performed by the means applied to rotate the crank shaft, such as an internal combustion engine (not shown). However, as pump 14 pumps oil from pool upwardly into chamber 46, piston 44 is directed downwardly and cage 24 moves to seated position, thereby closing the primary flow passage and causing fluid entering opening to follow the secondary flow passage through cage 24, around the serrated valve disc 30, and into the compression chamber 4 when piston 13 moves downwardly in its intake stroke. As the compressor piston 13 starts its upwardly compression stroke, the discshaped valve member is forced upwardly by the reversed flow of gas to seated position against the annular valve seat 29 provided by cage 24, thus closing the secondary flow passage. As a result, the compressed gas is forced through port 34 about valve member 37, into the exhaust chamber 31, and out port 35. Port 35 may in turn communicate with the condenser of a refrigerator system.

The loading of the compressor may be further delayed after crank shaft 5 begins rotation by the closing of valve 52. Until this valve is opened, oil will not pass from passage 16 into chamber 46. The valve 52 may be adapted for manual operation, or may be connected for automatic operation, as for instance, with a suitable thermostatic element which opens valve 52 only when an internal combustion engine or other driving means reaches a desired operating temperature, or with a controller responsive to suction pressure.

Furthermore, while the operation of only one valve unit has been described in detail, it will be seen from Fig. 1 that valve 52 may be set to shut off the supply of pressure fluid to both or either of the chambers 46 and 47, so that both or either of the compressor pistons 12 and 13 may be arranged to operate without a load. Thus, the load upon a large compressor consisting of several compressor pistons, compressor chambers and valve units, may be varied by loading or unloading the separate units, thus altering the capacity of the compressor as a whole.

Another embodiment of this invention is illustrated in Figs. 3, 4 and 5. An elongated and flexible leaf valve member 60 is secured by rivet 61 or by any other suitable means to the top wall of the compressor chamber 62. I prefer to tightly fit one end of valve 60 in a notch 63 provided in wall 64. The opposite end of leaf valve 60 is fitted loosely in a recess 65 in the wall of casing 66 so that the loose-fitting valve member 60 may flex downwardly within recess 65 to admit gas into chamber 62 and may also flex upwardly within recess 65 when piston 67 executes its compression stroke. As shown in Fig. 5, the width of elongated valve member 60 is less than the inner diameter of the lower portion of the valve casing 68 but is greater than the inner diameter of the lower tubular portion of valve cage 69 which is slidably mounted within valve casing 68. Moreover, as illustrated in Fig. 4, when valve cage 69 rests upon ledge 70 the valve seat provided by cage 69 is substantially in line with the lower end of valve casing 68 and is positioned to make sealing contact with flexible valve member 60.

A pair of exhaust ports 71, 72 are provided for each compression chamber and lead into exhaust chamber 73. In other respects the compressor structure is similar to the structure described in reference to Fig. 1, including the exhaust valve assembly which is not shown in Figs. 3-5.

The operation of this embodiment is as follows: As the compressor piston executes its intake stroke, gas flows into the valve casing 68 through opening 74, through the valve cage 69, and around the downwardly flexed leaf spring 60 into chamber 62. This occurs whether or not the valve cage 69 rests upon ledge 70.

As the piston 67 moves in its upward compression stroke, the gas in chamber 62 will be exhausted through the same passages by which it entered as long as the valve cage is not in seated position on ledge 70. Therefore, when the valve cage 69 is unseated, no load is imposed upon the compressor. When the valve cage is forced downwardly against ledge 70 by pressure fluid within piston chamber 76, however, the cage is then positioned to co-act with valve 60, as illustrated in Fig. 4. As the compressor piston 67 moves upwardly, the compressed fluid within compression chamber 62 flexes valve 60 upwardly against valve seat 75, thereby sealing the flow passage through valve cage 69 and causing the compressed fluid to flow through the exhaust ports 71, 72.i1 1to exhaust chamber 73.

' 'It is therefore apparent that the loading or unloading of any single compressor unit, and the capacity of a compressor consisting of multiple compressor units, depends upon the position assumed by the valve cage or cages. When valve cage 69 and its integral valve seat 75 are moved away from leaf valve 60, the compressor performs no work. When the valve cage is moved downwardly by fluid pressure within piston chamber 76, however, the leaf valve 60 may seat against the valve seat provided by the movable cage and the compressor will be in operating condition.

While in the foregoing specification, specific structures have been set forth in considerable detail for the purpose of illustrating embodiments of this invention, it will be understood that such details of structure may be varied widely by those skilled in the art without departing from the spirit of my invention.

I claim:

1. In a compressor apparatus having a compression chamber, a tubular valve casing having a flow passage therethrough, said casing also having a ledge on the inner surface thereof, a movable valve cage within said casing having the general configuration of a perforate hollow cone provided with a tubular portion extending from the base thereof and having a passage for the flow of fluid therethrough, said cage having a peripheral ridge defined by the base of said cone for the seating of said valve cage against said ledge, said movable cage also being provided with a movable valve seat adjacent the lower end of said tubular portion, and a movable valve member mounted for movement between seated and unseated position against the movable valve seat provided by said movable cage, whereby the flow of fluid through said casing from said compression chamber is prevented only when said cage is seated against the annular ledge and said movable valve member is seated against the movable valve seat provided by said cage.

2. The structure of claim 1 in which said tubular valve casing has an inwardly directed annular lip at one end thereof, said movable valve member having a generally disc-shape and mounted for reciprocal movement between unseated position against said annular lip and seated position against said movable valve cage.

3. In a compressor having a compression chamber and being provided with a primary flow passage communicating therewith, a valve stop adjacent one end of said primary passage, an opposed valve seat having a secondary flow passage therethrough and being movable between two positions within said primary passage, a valve member freely movable between a first position against said valve stop and a second position remote therefrom when said valve seat is in either of said two positions, said valve member having a dimension less than said primary passage and a dimension greater than said secondary passage, said valve member being cooperable with said valve seat for preventing the flow of fluid through said secondary passage only when said valve seat is in one of the aforesaid two positions and said valve member is in its second position, and means for moving said valve seat between the aforesaid two positions.

4. In a compressor having a compression chamber and being provided with a primary flow passage communicating therewith, a valve stop adjacent one end of said primary passage, an opposed valve seat having a secondary flow passage therethrough and being movable between a first and a second position within said primary passage, a valve member freely movable between a first position against said valve stop and a second position remote therefrom when said valve seat is in its first position and also when said valve seat is in its second position, said valve member having a dimension narrower than said primary passage and wider than said secondary passage for preventing the flow of fluid through said secondary passage only when said valve seat is in its second position and said valve member is also in its second position, biasing means for urging said valve seat away from said valve member and towards said first position, and pressure-responsive means for overcoming the force of said biasing means and for moving said valve seat towards said valve member and into said second position in response to a pressure condition produced by the operation of said compressor.

5. The structure of claim 4 in which said valve member has a generally disc shape and is free to move within said primary passage between said first and second positron.

6. The structure of claim 4 in which said valve member comprises an elongated strip having a free end movable between said first and second position for regulating the flow of fluid through said secondary passage when said valve seat is in its second position.

7. In a compressor having a compression chamber and being provided with a primary flow passage communicating therewith, a valve stop adjacent one end of said primary passage, an opposed valve seat having a secondary flow passage therethrough and being movable between two positions within said primary passage, a valve member freely movable between a first position against said valve stop and a second position remote therefrom when said valve seat is in either of its two positions, said valve member having a dimension smaller than said primary passage and larger than said secondary passage and being cooperable with said valve seat for preventing the flow of fluid through said secondary passage only when said valve seat is in one of the aforesaid two positions and said valve member is in its second position, and means for moving said valve seat sequentially between the aforesaid two positions in response to variations in a condition which is changed by the operation of said compressor.

8. In a compressor having a compression chamber, a movable valve for regulating the flow of fluid to be compressed within said chamber, an opposed valve seat having a flow passage therethrough and being movable between a first and second position, a stop adapted to limit the movement of said valve in a direction towards said seat, said valve being movable towards and away from said stop when said valve seat is in said first and said second positions, said valve being cooperable with said valve seat when said seat is in said second position for controlling the flow of fluid through said flow passage, and means for moving said valve seat between said first and said second position. a

9. The structure of claim 8 in which said valve comprises an elongated member mounted at one end upon said compressor and having a free end movable toward and away from said valve seat for regulating the flow of fluid through said passage when said seat is in said secand position. i

10. The structure of claim 9 in which biasing means are provided for urging said valve seat away from said valve and toward said first position, and pressure-responsive means are provided for overcoming the force of said biasing means and for moving said valve seat toward said valve and into said second position in response to a pressure condition arising from the operation of said compressor.

11. In a compressor having a compression chamber, a movable valve for regulating the flow of fluid to be compressed within said chamber, a valve seat having a flow passage therethrough and being movable between a first and a second position, a first stop adapted to limit the movement of said valve in a direction toward said seat, a second stop adapted to limit the travel of said valve in a direction away from said seat, said valve being positioned between said second stop and said seat and being unrestricted in its movement between said stops when said valve seat is in both said first and said second positions, said valve being cooperable with said valve seat when said seat is in said second position 'for controlling the flow of fluid through said flow passage,

598,283 and means for moving said valve seat between said first 1,291,854 and secondpositions.

I References Cited in the file of this patent UNITED STATES PATENTS 534,813 Christensen Feb. 26, 1895 8 Christensen Feb. 1, 1898 Haight Jan. 21-, 1919 FOREIGN PATENTS Great Britain Nov. 27, 1934 

